Sunday, June 19, 2011

Aculeata Agonistes: Soggy Mud Daubers & Muddy Thinking

 I think I watched too many Walt Disney wildlife programs when I was a child, because this wasp looked sad and soggy to me this morning (and yesterday and the day before too). But I know I’m just projecting my feelings onto the mud dauber: there is no data supporting the hypothesis that insects feel emotions like people and cats do.
 This particular mud dauber is Ancistrocerus waldenii (Viereck, 1906) and she was thriving when the sun was shinning.
 There isn’t any common name associated with the species on BugGuide or at the Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of theNortheastern Nearctic Region. Since the species seems to have been named after someone called Walden (or perhaps Walden Pond), I think Walden’s Mud Dauber will have to do.
 The generic name seems to be derived from the Greek ancistrum (fish hook) and cerus (an earthen pot). I suppose the former refers to the female’s curved sting and the latter to the mud nest. Walden’s Mud Dauber’ free-standing mud nests, however, are unusual among at least the local Ancistroceri – most nest in hollow twigs and use mud only for the partitions between cells.
 Given the last week of steady rain, one can see the advantage of a retreat less likely to dissolve back into the earth from which it sprang. Perhaps the wasp mixes in some hydrophobic material or cement as she works the mud into the scimitar-shaped additions which she stacks into tubular cells. I also wonder if they know bad weather is coming? After making a half dozen tubes perpendicular to the ground, and open to any rain until they were capped, this wasp constructed a tube on top of the others and parallel to the ground.
 The last few days, the wasp has been spending most of her time in this tube, glumly watching the rains fall. That’s a shame, because the caterpillars she was hunting included a nasty little vermin that makes a mess of our Ivory Halo Dogwood each year. Here's a paralyzed one that I rescued from a foraging Formica ant - it is dangerous to leave you brood cells open.

A larger caterpillar also taken is probably the Delphinium Leaftier (Polychrysia esmeralda (Oberthür, 1880)). 
 Interesting that she seems to go after caterpillars that hide themselves in folded bits of their host plants.
 It would be a terrible shame, if after all her hard work, this poor mud dauber had to watch her babies wash away in a sea of mud. This may be more Disneyesque thinking, but I prefer to think of this as a proactive measure of classical conservation biological control. Keep your parasites, predators (and pollinators) happy and you will have a thriving Home Bug Garden. I give you the first mud dauber umbrella (patent pending).


  1. This is great! Do you know the source of the 'mud' it's using? I know that after this week of on-and-off rain, mud is all over, but does it prefer using a more clay-like mud or does anything work?

    And I'm wondering if the horizontal tubes are a result of sagging in the rain rather than the weather fore-casting abilities of the wasp... ;)

    Cute umbrella!

  2. The horizontal tube was constructed on top of the perpendicular tubes before the heavy rains started, so I don't think it sagged and she just went with the slump. If she builds some more here, we'll see what happens.

    I watched the wasp do a lot of collecting in the wet moss near the base of the bubbler, but that may have been more for water to work the clay. No problem finding clay in this one time slough and one time bottom of Glacial Lake Edmonton.

  3. I can't begin to tell you how cute I think the umbrella is that you made for the wasp. I am just grinning from ear to ear. I felt sorry for her too when I saw that first photo of her huddled in her tube. Hopefully she is out hunting vermin soon.

  4. I'm not sure even Disney could make us identify with a wasp hero as you have! I was very puzzled and intrigued by your first photo. Really love the way the mystery unfolded.

  5. Great post just found your blog from a posting you made on mine.